Frightened Rabbit - The Midnight Organ Flight (optimistic in bits, and overall in a backwards kind of way)

Guided By Voices - Alien Lanes (!!!)

Idlewild - Post Electric Blues

mewithoutYou - Brother, Sister/It's All Crazy! etc

also, what I've heard from Andrew Jackson Jihad (esp people that can eat etc) is very optimistic and indie in equal measures, and you'll deffo wanting to check out the 'Dark Was the Night' compilation album cos it's basically 2 discs of what you're after. hope you check out some of these, I've basically just gone and named some of my favourite albums evar :D